Current findings suggest that, unlike other groups in the U.S., drug use and abuse increases in African American youth as they transition into adulthood. African Americans also show bimodal patterns of drug use with large numbers both heavy and low drug users. These findings highlight the need to identify factors that may be related to increases in drug use during early adulthood and those that contribute to heterogeneity in drug use within this population. Therefore, this study is designed to assess the impact of genetic risk factors (i.e., a family history of drug dependence;genetic markers for depression) and environmental stress (i.e., exposure to interpersonal and community violence) on psychological functioning and drug use,and abuse in a community-based, non-clinical sample of African-American male and female young adults aged 18-25 (n=600). There is accumulating evidence that genetic factors, such as a family history of drug dependence, and environmental stress, such as violence exposure, are significant correlates of drug use. Depression, which may be precipitated by both genetic factors and environmental stress, is also significantly related to drug use and common neurochemical pathways may mediate both stress responses, such as depression, and drug use. Despite these findings, few studies have examined successive relationships between genetic and environmental risk factors, psychological functioning and drug use and abuse, especially in African American populations. As a result, we know little about the degree to which individuals with genetic markers for drug use and/or depression may, when faced with environmental stress such as violence, have a greater likelihood of psychological distress such as depression and subsequent drug use or abuse. This study will examine relationships between genetic and environmental risk factors for drug use and depression, psychological functioning, and ATOD (alcohol, tobacco, and other drug use) in a sample of African American young adufts. It may be particularly important to examine these relationships in African Americans who are at risk for exposure to violence and drug use and abuse as they transition into adult roles and responsibilities. The findings may also assist in identifying subgroups of African Americans who may be at high risk for depression and/or drug use or abuse in response to urban environmental stress. The proposed study, with its focus on gene-environment interactions influencing psychological functioning and drug use/abuse in African American youth is consistent with the proposed P20 application which is designed to address health disparities in child and young adult populations in substance use, violence and chronic disease.